A Novel Approach for the Optimal Design of a Vertical Cellular Breakwater Based on Multi-Objective Optimization

Abstract

In this paper, a methodology based on multi-objective optimization is proposed for the optimal design of a vertical cellular breakwater, consisting of prefabricated rectangular cells with two vertical permeable walls supported by two rows of vertical circular piles. The vertical wall consists of a perforated upper part and a lower part with horizontal slots. Maximization of wave energy dissipation coefficient and minimization of the volume of material used in the breakwater are the two objectives considered. The methodology employed in this study uses a theoretical model to determine the wave energy dissipation coefficient and material volume in the vertical cellular breakwater. The most widely used and acceptable eigenfunction expansion method is employed to evaluate the hydrodynamic coefficients of breakwater. The results obtained by the eigenfunction expansion method is evaluated by conducting experiments and by comparing with the published results. The two objectives to be achieved in the design are conflicting and it is quite difficult to satisfy both the objectives simultaneously. A multi-objective optimization tool based on genetic algorithm (GA) is employed to find the pareto optimal set of solutions in a search space. To arrive at the best-agreed solution from the obtained pareto optimal set of solutions, some practical preferences are considered. Results indicate that this approach can be effectively applied for the optimal design of a vertical cellular breakwater.